Drafting instrument



A. E. MAGNUSON.

DRAFTING INSTRUMENT.

APPLICATloN FILED1UNE30,1919.

BY l \J// z ATTORNEY UNITED STATES PATENT OFFICE.

ANDREW E. MAGNUSON, OF'NEW YORK, N. Y.

DRAFTING INSTRUMENT.

Application alea :ruae so,

To @ZZ whom, it may concern.

lle it lmown that I, Amnunv E. MAGNU- soN, a citizen ot theUnitedStates, and a resident of the borough of li/Ianhattan, in thecounty, city, and lltate .of New York, hare invented certain new anduseful Improvements in Drafting Instruments, of which the following,` isa specification.

rIlliis invention generally relates to the art olf mechanical drafting,and more especially it appertains to instruments or implements wherebydistances between lines can be accurately measured, and the latter maybe drawn uniformly at the desired internals apart. For the turtlieranceot conciseness and precision, it willbe described and shown hereinparticularly with relier ence to T-squares and drawing boards combined.

rlhe primary object oi." the invention is to de n an improved implementfor the purpose contemplated, which shall be capable of accuratelymeasuring spaces between lines that have been or are to be drawn,`without using' a separate scale or similar means` to ascertainthedistances at wl 'ch the lines were or will be laid relatively to oneanother.

il. secondary object is to supply an implei'nent of the genus alludedto, including co ,ingr measuring' elements, one olf which niiirmally nio7able over theiother, while the latter 'may remain stationary or admitalso ot being moved to advance or retract the points at which themeasurements will commence, so as to suit various requirements.

il.. third object el' the invention is to prodnrc an iniprot'edT-seluare olf the cliaracter set 'forth allording' an accu ate means ofspacing' the lines to be drawn, according to 'ironer use thereof will beunderstood at l i i the draitsi'nan, even though a becnre by and .workwill be performed ner,

` n hout tear or hesitation, but intelligently as well asexpeditiously'.

il. further object is to provide an implement of the clins mentionedpermitting the standard oli measurement, and

Specification of Letters Patent. Patented All. 10, 1920.

1919. 'Serial No. 307,711.

T-square to be quickly applied to or removed from the drawing-board, andalso to be rendered inoperative to the end that it may be used in theordinary manner, if and whenever desired.

Still another object is the provision of an implement of the typereferred to, the actuating mechanism whereof shall be of small comparaand i'ior the most part shielded from exposure, so that it will be fullyprotected and may not cause the least interference or inconveniencewhile the work of dra-tting, is being` carried out.

it still .turther object is to devise an implement of the hindspeciiiedcomposed of Vbut few parts, that can be produced from readily zwallablematerial mostly anywhere,

and easily assembled with the aid of common tools, by plain mechanics,at a slight expense.

Other objects and advantages of the in- Vention will become apparent asthe specification proceeds.

llVith the aforesaid objects in View, the invention consists of thenovel combinations and arrangements ot parts hereinafter described intheir preferred embodiments, pointed out in the subjoined claims, andillustrated on the annexed drawing, where in like parts are designatedby the same reference characters throughout the several views.

In the said drawing,-

y Figure I is a top plan View, showing one corner olf a drawing-board,with this improved T-square in operative position thereon, the latterbeing` shown "on a reduced scale and with its blade broken transverselyintermediate the ends;

II an enlarged sectional elevation, including` a fragment ot thedrawing-board and a broken View of the T-square, the section runningacross the head ofthe latter and lengthwise of its blade in a`substantially central plane;

Fig. III is the perspective View of the carrier and bearing platepertaining to the implement,looking at the under side of the bearing'plate alone, as seen irom the upper side thereof;

Fig.` V is a detached perspective View of the said carrier;

Fig. VI is a top plan View of a revoluble index, included in theimplement.

Fig. VII is a perspective view of the operating pinion, including itsspindle and parts thereto appertaining; and

Fig. VH1 is a perspective view, on a slightly larger scale, showing thehead of the T-'square and a fragmentary part of its blade, with arecess, perforation, and incisions therein made.

In these views the letter A. represents a well-known form oindrawing-board, to which the invention is readily applied. On the face otthis board appears a T-square of customary outline, the same comprisinga head B; and a blade C. it is understood that the parts here named arenot new in tiemselves, and therefore pertain to the present inventiononly in so tar as the structural details and accessories hereindisclosed are concerned.

The inner side of the head B aforesaid is adapted to be moved closetoand in parel' lelism with the ad`acent edee of the board A, the blade Cmeanwhile sliding` over the surface of the board, ni the usual manner.The head however is not intended. to touch 3 7 the board but merel ifollows the edeje n. l: 1 e thereof, goino past the teeth ci a rack-oar1, attached to the latter. rFhe rack-bar may be held to the edGe of theboard h i anv c 1 suitable means, for instance, oy screws, as 0 l' t l'F' T i a, as inc ica ec in ig. i.

A pinion 3, adapted for engagement with the teeth orn the rack-bar 1 is)laced in a recess 4, cut into the head B, directly under Y that part ofthe blade C which is .stened to the same. The recess 4 may be circularor of any other approved shape, but in a y case is open laterally, as at5, to enable the dented perimeter or the pinion to approach and engagewith the corresponding centate face of the rack-bar.

Preferably and as shown, the pinion 3 is held in suspension from aboveby a spindle 7, to which it is fastened. As seen in Fig. 1l, the spindlepasses upwardly through a carrier presently to vbe described, and isjournaled at opposite points therein. it is also reduced in diameter atits upper end, and terminates in a threaded shanlr 10, engaged by abinding-nut 11.

The carrier, above referred to, is conveniently formed oiC a singlestrip of metal bent upon itself to constitute an open-sided structure,the component parts of which all appear in Fig. V, and most oiitliemalso in Figs. II and HI. In the exeinpliiication given herein, thecarrier include two suhstantially parallel, top and bottom portions 12and 13, a forward wall 1-i joining the same, and a iianged pendant 15,at the rear.

Referring particularly to Fig. 1I, it will be observed that the largerpart of the spindle @immediately above the pinionL 3, finds a bearing.withinA an opening 18, formed in the bottom portion 13 of the carpart19, of the spindle.

rier. Similarly, the top portion 1Q ot the latter is provided with acorresponding aperture through whieh passes a redueed This aperture issurrounded by a collar Q0, `formed integral with the top 12 of thecarrier and wherein is iitted the said reduced part 19.

rhat portion oiv the blade C, which was previously referred to asfastened to the head B, is apertured, as at 2l, to permit the passagetherethrough oi the upper part ot' the before described carrier, withits eonnected parts. rEhe top 1Q ot the said earriei just projects abovethe aperture 21, and is held at that elevation by ineans ot a snpportingplate 22, adapted to be secured as by screws entering holes i in theplate 2:2 and corresponding holes Qi in the blade its shown in Figs. llland lV, the carrier is made to project upwardly through a suhstantiallyrectanguler opening L, in the plate Q2, and its top 1Q is arranged tohear slidahly upon oppositely-located lugs Lt', projecting inwardlytroni the side Vedges o t the latter-named opening.

Upon the top portion 12 et the earrier and overiying the supportingplate 22. is disk or dial 3G, which is centrally apertured, to embracethe said collar i() of the carrier. The upper tace ot this dish bears anannular series of marl' n; oeeuring at regular intervals apart i'ioinone another, and denoting, ior instance. in iraetions of an inch or ot'a meter, or other unit oiE linea r measure, any distance traversed b vthe T- `niare as it is caused to travel over the surface ot thedrawiiig-board. The, distance is pointed out by an index 32. rigidlyconnected with a receiving portion 33, ot the spindle 7, situatedintermediate of the aforesaid reduced portion 19 and the threaded shank10. As detailed in Fig. Yi. the index 32 has an integral huh $4-,perforated centrally, as at 35, to lit around the receiving portion '33,and both the latter and the perforation are provided with co-actingstraight edges 3G, 37, at one side. to prevent independent rotation. Theindicator dislr or dial 30 and the index iii) revoluble tliereover areheld in place against the carrier top and the pinion spindlerespectively, through the action ot the binding-nut 11, engaging thethreaded shank 10, aforementioned.

A resilient retainer or clamp at) is provided to hold the disk 30 bothrotatably and slidably with relation to the supporting plate 22. whilethe said dial has only a eircular motion relatively to the top portionof the carrier and its collar. This retainer may consist of a singlespring wire anchored at 40 to one end of' a ledge or outwardly extendedliange 41, of the pendant 15 of the carrier, and thence reachingrearwardly so as to grasp the superimposed disk ti (l.

30 and plate 22. The wire may be bent upwardly, as at 42, tobear againstthe under side of this plate, and downwardl as at 43, upon the uppermargin of the dis 0 The iecess 4, perforation 2l and opening 25 are allmade sufficiently large to admit of sliding the carrier forward and backtherein, either to disengage the pinion from the rack, or to re-instatethe same in their meshing relation. The indicatorl disk held by theclamp or retainer 40, it will be seen partakes of the same movement, theportion of the clamp which grasps the disk and plate thereunder beingarranged to slide in a slot 45, made in a rearward extension 46, of theplate.

The sliding back and forth of the said carrier and parts theretoconnected is effected by means of a detent 48. The latter also mayconsist of a single spring wire attached, as at 49, to the top 12 ofthecarrier, and extending thence to the said slot 45. A head 50, on therear end of this detent, serves to hold it engaged with the upper faceof the extension 46. Notches 51, 52, lateral to the slot 45 serve askeepers to retain the detent in a fixed position, after it is drawnforward or rearward as the case may be. Iii passing from the point ofattachment 49 to the slot 45, the detent wire is made to run through anotch 53, in the pendant l5. Now, in order to disengage the wire fromeither of the notches 5l or 52, it is strained by being bent upon thecorner of the carrier where the notch 53 is located,

and therefore the tendency of the wire is to carry its outer or rear endinto either of the notches first mentioned. Assuming that the outer endof the wire engages the notch 52, as represented in Fig. II, the carrieris then positioned so that the pinion 3 will be in mesh with the teethof the rack-bar l. 1When it is desired to disengage the inion from therack, then the head 50 of t e detent is pushed sidewise to retract thewire from the notch 52, and the detent is pushed forward through theslot 45 to effect disengagement of the pinion and rack, whereafter thedeteiit is released and that part of the wire thereof which adjoins thehead 50 automatically enters the forward notch 51., due to the stressexerted upon the Wire by its being bent around the said corner of thecarrier. A channel or slideway 55 is cut into the blade C, at the endthereof intended to be placed upon the edgeof the drawingboard A, sothat the wires composing the said retainer and the said detent will havethe requisite clearance for their effective manipulation. The slideway55 is covered by the extension 46 of `the supporting plate 22,hereinbefore mentioned.

As before intimated, the face of the dial or disk 30 bears a series oflines drawn so as to constitute some preferred scale of measurement.These lines `may be iinpresscd into the dials surface, or otherwiseproduced. Whatever is the measuring system adopted, however, the seriesof lines is such that it will readily accommodate itself to the same.The lines, it is to be noted, are disposed in a circle, commencing andterminating, so to say, at the one point, namely, that indicated by zero(0) in Fig. I. The circle may be divided into sections representing, forinstance, quarters of an inch, orlive millimeters, and these sectionscan also be subdivided, into smaller intervals. In either case, theindex 32 will point out the exact subdivision line or lines expressingdistances which the draftsman wants the T-square to traverse in layingout or performing his work. The distances may b e computeduninterruptedly, as the invention 'admits of it. But, in changing fromone interval to another While making the computation, the operator willfind it to his advantage to avail himself of that peculiarity of theinvention which allows the rotation ofthe dial independently of theindex. This will enable him to bring the zero point of the former to thelatter at any time desired, and therefore will facilitate greatly thecomputation of intervals. The edge of the dial is knurled, in order thatit may have a convenient grip for the fingers in making* the desiredadjustments.

A concavity 58, which may be of crescent shape, as shown in Figs. I, IIand VIII, is provided in the end of the blade C that overlies the head Bof the T-square. The `knurled edge of the'dial aforesaid advances overthe inner margin of this concavity, and therefore can be reached easilyby the operator placing the thumb or a finger' into the depres-l sion.I-Ie is thus enabled, if he so chooses, to 'turn the `dial with the samehand that guides or pushes the head of the instrument over the surfaceof the drawing-board, as the work progresses.

Although the operating mechanism herein described has been shown-in theannexed drawing as being centrally located with relation to the head liof the T-square, it is understood that it could be attached thereto inany other required position. It is also obvious that notwithstanding theblade appears to be rigidly connected to the head of the T-square, theseparts also can well be made inter-relatively movable. It is furtherconceivablethat instead ofrelying on the sliding of the T-sqiiare uponthe drawing-board to cause. the pinion 3, actuated by the teeth of therack-bar l, to move the index 32 over the dial 30, the same result couldbe achieved by turning the nut 1l. The latter, in that case, wouldimmediately shift the index the exact distance wanted, and incidentallywould serve to rotate the pinion positively in such a manner as toadvance the this device has been shown and described, it

will be understood that changes in the form, arrangements, proportions,sizes and details thereoil may be made, without departing from the scopeof the invention as defined by the appended claims. Y

Having described my invention, what l desire to secure by Letters Patentand claim l. A. drafting implement comprising a T- square combined witha drawing board and including a carrier supported from the head ot' saidT-square, a revoluble element sustained by said carrier, a memberattached to said drawing board so as to be engaged Aby said element in amanner to produce a step by step movement thereof along said board, anindeX operatively connected with the ele ment, and a graduated dialrotatably mounted on the carrier under said index, the arrangement beingsuch that the index coacts with the graduations onV the dial and thelatter is adjustable relatively to the former.

2. The combination with a T-square and adrawing-board, of a supportapplied to the head of said T-square near one end, a earrier slidablerelatively to said support, a revoluble element journaled in saidcarrier, a dentate member positioned at one edge ot said drawingboardf'for engagement by d element, an index connected to revolrelconjointly withthe latter, and a cooperating dial independently movablewith relation to said index. l

3.' The combination -with a T-square and a drawing-board, ofV a carrierslidably mounted on the head oi said -square, a gear element revolublysuspended from said carrier, a member fixed to one edge oi". saitdrawing board arranged to receive the teeth of said element, a dialrotatable independently on the carrier, an index movable relatively tosaid dial concurrently with the revolving of the element, and means forsliding the carrier together with the dial from a point beyond said headso as to move the gear element into or out of engagement with saidmember.

4. The combination with a T-square and a drawing board of a rack memberattached to one edge of said drawingboard, a pinion arranged to meshwith said member so as to move longitudinally thereof, a carriersupportingsaid pinion, a dial rotatable independently of the latter onsaid carrier, an indexto saidV dial conjointly rovoluble with thepinion, and means transverse to the member for sliding the carrier to orfrom the same along said ed0`e of the board.

5. The combination with a T-square and a drawing board, a supportoverlying the head of said T-square, a carrier slidable on said support,a pinion suspended from said earrier, a rack fixed to one edge ot saiddrawing` board in position to be engaged by said pinion, a dial on thecarrier above its said support, an index connected with the pinion so asto revolve over said dial, and means for sliding the carrier sustainedby the same support.

6. The combination with a T-square and a drawing board, o" a carriermounted on the head oi said 'l`-s piare, a gear-element revolublysupported by said carrier, a rack member lixed to one edge of saiddrawing board in position to be engaged. by said element, a

Adial rotatable on the carrier, an index arranged to be revolved oversaid dial Afrom the gear element, and retaining` means holding the dialagainst rotation while said index is revolved thereover.

7. The combination with a T-square and a drawing board. of a supportoverlying the head of said T-square, a carrier slidable on said support,a gear element suspended from said carrier, a rack member engageable bysaid element at one edge of said drawing board, a dial rotatably mountedon the earrier, an index revolved over said dial from the element,`means for sliding the carrier, and other means enacting with the supportand the dial to hold the latter against displacement while permittingits independent adjustment relatively to said index.

rEhe combination with a drawing boa rd. o a "tm-square the head whereofis provided with a recess and a passage oilset therefrom. a rack memberattached to one edge of said drawing board, a gear element engageablewith said member through said recess adjacent to said edge, a slidablecarrier supporting said element in the recess, a dial on said carrier,and means located in said passage serving to slide the carrier with thegea r element either toward or away from the rack member.

9. rlihe combination with a drawing board. oit a T-square the head oitwhich is provided with a recess and a cavity, a rack fixed to one edgeof said drawing board` a pinion in said head capable of' meshing withthe teeth of said rack through said recess adjoining said edge, acarrier sustaining said pinion within the recess, a dial rotatable onsaid carrier adjacent to said cavity, and an index operatively connectedwith the pinion to revolve over said dial.

l0. The combination with a drawing board and T-square, of a rack fixedto one edge of said drawing board, a pinion carried by the head of saidT-square and positioned for engagement with said rack, a spindle towhich said pinion is secured. said spindle having a neck, a shoulder anda threaded shank` a carrier wherein the part ot the spindle adjoiningthe pinion is journaled, a portion of said carrier being adapted toreeeive said neol, a dial rotatable on the earrier around the neellz, anindex carried by said shoulder in position to be revolved over said dialfrom the pinion, and a binding element arranged to take over saidthreaded shank so as to bear upon said index.

11. The combination with a Tsquare and a drawing board, of a supportingplate overlying the head of said T-square and ineluding an aperture,lugs extending from opposite sides of the latter, a carrier slidablymounted on said lugs Within said aperture, a gear element having aspindle journaled in said carrier, a rack member' attached to one odgeof said drawing board in position to be engaged by said element, a dialrotatable around said spindle above the carrier, an indeX fixed to thespindle so as to be rotated thereby over said dial, and means forsliding the carrier on the lugs of said plate in order to place the gearelement in or out of engagement with the rack member.

12. The combination with a T-square and a drawing board, of a supportingplate formed With a passage having lateral keepers, a carrier slidableon said plate, a gear element supported from said carrier, a rack memberfixed to one edge of said drawing board so as lto be engaged by saidelement, a dial rotatable on the carrier, an index revolnble over saiddial through the action of the gear element, a retainer normally holdingthe dial from rotation and having one end slidable in said passage, anda detent for sliding the carrier and thereto connected parts, saiddetent being slidable also along the passage and adapted to enter eitherone of said keepers for looking the gear element either in or out ofengagement With the `rack member.

ANDREW E. MAGNUSON.

